Re DAS: no you can’t connect multiple systems to it. iSCSI and NFS on a SAN or NAS support multiple connections but the OS or app needs to support it.
You should limit your connections to one machine per volume when using iSCSI or nfs. Smb would probably the best for multiple connections.
I thought that osx also saw active user count drop? I think it’s people simply don’t need a laptop/desktop at all.